Guard for table saws



April 17, 1956 F, N. BRETTHAUER GUARD FOR TABLE SAWS 3 Sheets-Sheet 1 Original Filed April 20 1951 @w m m w Z N w R m k N.

m M 2 Q I I I 7 0 n M WHMW 3 WMLA T w A April 1956 F, N. BRETTHAUER 2,742,063

GUARD FOR TABLE SAWS Original Filed April 20, 1951 5 Sheets-Sheet 2 :2 m {1 mm w H? M T w av I. K F

INVENTOR. fimvx M 59577/441/52 ATTORNEY.

April 17, 1956 F. N. BRETTHAUER 2,742,063

GUARD FOR TABLE SAWS Original Filed April 20, 1951 3 Sheets-Sheei 3 INVENTOR FRANK N BRl-TTHHUER ATTORNEY BY/M M United States Patent GUARD FOR TABLE SAWS Frank N. Bretthauer, Bronx, N. Y.

7 Claims. (Cl. 143159) This invention relates to a guard. for table saws.

This application is a. continuation of application Serial No. 222,046, filed April 20; 195 11,. and? abandoned as. of April12, 1954..

With table saws the customary: guards are fixed in a bed: in. a given location and extend; out over the saw. They are commonly pivoted. in such, a manner that they can be lifted up to permit inspection, or adjustment, of the saw, but for many purposes the guards, themselves, are in the way, so. that many. operations are performed with the guard removed.

Moreover, the manner in which such. guards are sup ported from the table: make it troublesome to remove and; replace. them; the operator to remove; the guard and operate without it, even when operations. are performed with. which the guard] could. be. used.

It is an object of, this invention to provide: a guard which. may be removed and replaced: with great ease, and which when replaced? will be accurately positioned for use and be firmly held; there.

It is. a further object to. provide a combination guard and table such that the guard; may protect. theuser from the saw for awide variety of different operations, and

when necessary may be removed. from one: position on the; table and; placed on another, with the greatest by simply liftingit up, and placing: in the new position, and yet,,when so positioned, will resistdisplacement while m. use.

It, is. a further object to. provide a: guard. which while offering; full protection will" yet: permit visuaL inspection of the-exact operation being carried out on: thev saw;

It is a furtherv object to provide; a guardzwliich itself may. be useditoassist' in holding the stock inv place, with some operations, so; that more performed".

It. is a. further object to provide a; guard which may be. varied. in its height. tothe: table,. to: accommodate differentt thicknesses ofi stockaudl which: may be adjusted to and from the saw,,to.=accommodate;diiferent'operations.

A.further-object is toiprtoyidea guard which, may be held rigidly in alignment; in; whatever position it: maybe placed. A further objectis to providealguardicarryingaaimeme ben which may. be: projected below the surfaces. of the.

guard:v toengage. stock, as; the: latter is; moved. past the:

saw, to assist in holding. therworkjimexact position with reference tothesaw; as for example: in ripping or groosiing; of thestock.

Itisafurthen object toprovide adevice of the: charactorI described.- which may be held ina: horizontal plane so that there; is constantly a tendency for ease,

accurate work, may: be.

and-maybemoved downwardly to exert: pressure ontthe:

work tQrPI'QVeIltE kick back.

It is'afurther. obj cttQ-provide a guardiwhich' may be used to guide the work in; various capacities: and: which may be,adjustedtoqzserfectalignmentwith the saw.

It is a further object toxprovideiaz guardi which. may

readilt', be; attached or removed by tiltingthe: guardi but 2 which by a simple mechanism may be retained rigidly in place by a twisting movement when used as a Work guide.

It is a further object to provide a guard of the kind which is adapted to exert pressure on the work but having an element capable of yielding under excessive pressure without damage to the other parts.

It is a further object to provide a device of the" character described which will serve-as an over riding transparent fence, so that the work may be retained in place while still giving perfect visability to the operation.

The invention accordingly comprises a device possessing the features, properties and the relation of elements which. will be exemplified in the device hereinafter described and the scope of the application of which will be indicated inthe claims.

For a fuller understanding of the nature and objects of the invention, ing detailed description taken in connection with the ac= companying drawings, in which:

Fig. l. is a top plan view of the guard forming a part of this invention, the saw being shown in dotted lines;

Fig. 2: is a front elevation showing the guard mounted on the table in position for rip sawing, or face grooving;

Fig. 3 is a plan view of a guard applied to a table saw in position for ordinary cross cutting for end trimming;

Fig; 4 is a front elevation of the same;

Fig. 5 is aview similar to Fig; 3 with the guard in position for cross cutting when the cut is materially spaced from the end of the board;

Fig. 6 is. a front elevation of the same; I

Fig; 7 is a front elevation with the; guard in position for: edge grooving;

Fig. 8 (Sheet. 1) isa detail section along the lines'88 of Fig. 1;

Fig. 9 is a Fig. 2;

form of the device;

Fig. 11 is a detail.

In the drawings the numeral 1-0 is-the table of a table saw, having a slot 1 1 through which the rotary saw- 12' projects. The numeral 13 is a cut-off guide having; the usual strip 14 sliding in a groove 1'5 in the table parallel to and to the left of the saw. The tableisalsoprovided with a rip fence which can be mounted in any customarymanner, not here needing to-beshown;

In accordance with this invention there is provided a guard which may be set: onthe table in any' one of three positions, so that it may extend over or protect the saw, no matter what the nature of the Workto' be performed: may be; Que of these positions is marked A to the. right of the saw, one is marked B to the rear of. the saw and one: is marked saw. (Figs. 3t'o 7*) p It! is an important phase of'this invention that the guardi shall be readily changeable from-one oftliese'posh tions to. another; more readily, in fact, than it can be removed and set on the: floor. This isfimp'ortant; because thereisalways a temptation on the parrot an operatorto takejoiiftlie. guard in changing from one form;

of work to another andset the guard; aside, rather than take thetroublet'o. set it up for the new type. of'work m1] This; frequently causes u the machine: to. be. .In the present. invention; thistemptatiom is.el iminated; because there-is auscful positionvfor the guard: for e v'eny;normal use-to whichi V the saw. can be.put,.involving=any dangerfl'.and-ifisteasien' 1 be. done. operated. without a guard.

to putibinto; an operativeipositionrthan to set ittasidei.

'Iloz accomplish this: result the guard comprises pri i reference should be had to the" follow'-' detail section along the lines 99" of marily a head 25 adapted to rest upon and engage the table and a guard arm 26 slidable in the head toward and from the saw. The head is provided with three lugs 27, 28 and 29 upon'its underface, which fit into openings 27a, 28a, and 29a in the table. Openings 27a, 28a and 29a are provided at each of the positions A, B, and C.

As here shown, the table is made of sheet metal and each of the lugs 27 and 28 is provided with an outwardly extending finger 27b, 28b at its bottom and in position to engage the undersurface of the sheet comprising the bed, at the edge of the hole. The lug 29 is similarly provided with an outwardly extending finger 29b for a similar purpose. Each of the openings 27a, 23a, and 29a is slotted to permit a slight movement of the head toward and from the saw, so that in its position most remote from the saw the fingers 27b, 28b and 29b will hold the head on the table, but when it is slid slightly toward the saw, the finger 29b, which may be slightly shorter than the other two, may be freed. In this position the guide arm may be raised up, tilting the head about its far edge until the fingers 27b and 28b are also disengaged; whereupon the whole guard may be removed. it is readily inserted in any other position by a reverse movement; the lugs 27 and 28 are readily inserted while the head is tilted and they then serve as guides to insert the third lug 29. As soon as the head is in place it may be shoved back from the saw to engage the finger beneath the table, where it will be held firmly in place. A handle D may be provided to lift the device.

The head comprises a tubular member 30 of rectangular cross-section and mounted within it is a block 31 of the same width as the interior of member 30, which can be raised and lowered within the member 30 by a vertical screw 32 journalled in the top wall 30a and bottom wall 30b of member 30 and engaging a threaded opening 33 in block 31. The block 31 has two horizontal rectangular holes 3435 in which slide the bifurcated ends 3637 of guard arm 26. The bearing of the ends 3637 in holes 3435 is tight enough to support the guard arm above the saw with the requisite rigidity and yet to permit it being slid through the holes to move to and from the saw.

In order to move the guard arm in and out, the edge of the bifurcated end 36 is cut with rack teeth 40 to mesh with a long pinion 41 journalled at 42 in the bottom wall 30b to member 30 and urged upwardly by a spring 43, and journalled in the upper wall 30:: and operable by a knob 44. The spring 43 tends to push the top end of the pinion 41 up against the undersurface of upper wall 30a to keep it from rotating too freely.

The outer end of the guard arm has mounted upon it a flat shield 45 preferably of a transparent plastic. This fiat shield serves directly as the saw guard and at the same time permits the operations of the saw to be observed. Flat shield 45 has a groove 46 in its underface in which slides an adjustable pressure plate 47, also of plastic, and this pressure plate is adjustably held in place by a screw 48 and wing nut 49. The groove 46 is shaped as a cam so that as the pressure plate is moved in the groove it is forced downwardly with its leading edge below the bottom face of plate 26. This screw moves in a slot 50, as the pressure plate slides in groove 46.

In the modification disclosed in Figs. and 11 the hollow head 61 has mounted within it a block 62 vertically slidable on vertical pins 63 and its vertical position is determined by a screw 64 journalled in the top and bottom walls 65-66 of the head 61, and threaded into the block 62. The top bearing of screw 64 comprises a bushing 67 yieldably held in the upper wall 65, being held in place by a deformable plate 68, whereby if excessive pressure upward be exerted on the guard, the plate 68 will yield, freeing the screw 64, permitting the guard to rise without any of the parts being fractured.

The head 61 is detachably attached to the table 10, shown in Fig. 11, by two pins 70 upon the head which fit into round holes 71 in the table, and a screw 72 which is journalled in the upper and lower walls 65 and 66, and screws into a threaded opening 73 in the table. When the screw 72 is released the entire guard may be tilted up around the rear edge 74 of head 61 thereby freeing it completely from the table. To make this possible the pins 70 may be made cylindrical of a diameter fitting closely in the holes 71 on the side remote from the saw, but are tapered off on the side toward the saw, as shown at 75 to permit the tilting action while yet maintaining rigidity when flat upon the table. These pins 70 are held in the head 61 by screws 70a so that they may be raised or lowered to fit tight into holes 71. A knob 76 on top of the screw 72 facilitates tightening and releasing it.

The fiat shield 77 is attached to the head 61 by rods 78 slidable in bearings 79 in block 62 and fastenable at any desirable setting by set screws 79a.

The shield 77 comprises primarily a flat transparent sheet, such as Plexiglas, which lies over and is attached to the rods 78 by screws 80. It is desirable to provide a very limited lateral play in these screws when not tightened, so that on any particular table saw the shield can be aligned accurately with the saw While the screws are loose and then held, when the screws are tightened, into position.

The shield 77 is provided with a downwardly extending flange 81 on each lateral edge, and with a flange 82 on the end toward the saw. A plurality of spaced vertical holes 83 are drilled through the shield and the flanges 81, so that a wooden stick may be attached below the shield, at any desired angle to the saw to serve as a work guide. This is done simply by placing the stick beneath the shield at the desired angle and attaching it by nails through the holes 83 which overlie it.

A block 84 extends down from the shield and holes 85 are drilled clear through the shield and block, another hole 86 extends through the shield and part way through the block to receive a pin 87. When desired the pin 87 may be inserted in one of the holes 85, extending below the block 84 so that it may be moved up against the edge of a piece being sawed to serve as a guide.

A plate 90, pivoted on a horizontal pin 91 has its lower edge providedwith points 92 which may move below the bottom face of flange 81 to engage the face of the work. These teeth are spring pressed downwardly by a spring 93. A screw 94 threaded into the shield has its end in position to engage a part of the plate on the other side of the pin 91 from the points, so that by screwing down the screw 94 the points may be raised. A handle 96 is attached to the shield at approximately the center of gravity when the guard is in place.

These two embodiments of the device are similar in function and are interchangeable, except that the holes in the table are different, as has been described. The operation of the device, therefore, is identical. Both forms are usuable in positions A, B and C.

When the device is used for ripping, or for cutting longitudinal grooves in the face of the stock, the guard will 'be put on the table in the position C, as shown in Figs. 1 and 2. The rip fence will be adjusted to proper position and the flat shield extends out over the saw. In this position, the pressure plate 47 on the pin 86, is moved over to contact the left side of the stock so as to hold it against the rip fence. The flat shield will be adjusted to a height to give the saw free play beneath it.

When the saw is used for cut-off operations, the guard will be moved into position A and the shield will be moved over the saw far enough to cover it and raised to a position just above the work, or if desired, the shield may be raised above the height of the rip fence, thereby permitting the rip fence to be used in this position.

Mitering, flat or vertical dadoing, or end rabbeting may be done with the guard in position.

If, however, a board is to be cut across too far from the end to pass the head in position A, the guard will be moved to position B, extending forwardly over the saw. In this manner both halves of the board can freely pass the saw beneath the guard.

Fig. 7 shows another manner in which the guard may be used in position C, where the board is on edge with the shield bearing against the face of the board. In this position, with obvious variations of technique, the guard may be utilized in such operations as edge grooving, feathering, drop sawing, tongueing, grooving, plowing or rabbeting.

Moreover, for example, with the guard at B, by tilting the saw, or by tilting the cut-off guide, mitering, either flat or vertical, or feathering and moulding cutting may be performed, all under full protection of the guard.

It will be readily seen that in place of the means here shown for holding the head in place, I may readily employ any form of orifice in the table with which a corresponding member on the head may engage, to position the device, but it is preferably arranged so that the end of the guard toward the saw may readily be lifted by the handle, tilting the head about its remote end, and its balance will be preferably as here shown, so that it will be at rest in this tilted position, to permit adjustments of the saw parts. Thereafter it may again be turned back into place.

It will be clear also that when so tilted, it is free from engagement with the table, and it may be lifted off completely and just as easily inserted at another of the positions. Thus it is very simple to fold it out of the way, or to change its position, at will.

Since certain changes may be made in the above construction and difierent embodiments of the invention could be made without departing from the scope itself, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all of the scope of the invention which as a matter of language might be said to fall therebetween.

What I claim:

1. A guard assembly for a rotary table saw, having a bed, and comprising a head detachably attached to the bed, a block vertically adjustable on said head, a horizontal arm slidable in said block toward and from the saw position, a guard comprising a flat transparent sheet carried by said arm to a position over the saw and having its peripheral edges extending, when on the bed, downwardly toward the bed of the saw; whereby the guard may be caused to bear downwardly upon a work piece without itself engaging the saw.

2. A device according to claim 1 in which the vertical adjustment of the horizontal arm comprises a vertical screw journalled in said head and threaded into said block whereby said screw may cause said guard to exert vertical pressure on a Work piece.

3. A guard assembly for use on a table saw bed having openings therein, and adapted to be mounted on the bed, and said assembly having a horizontally projecting arm carrying a flat transparent guard, said assembly including a head having downwardly projecting pins on the side of its bottom face remote from the guard adapted to project into said openings in the bed, said pins being shaped to permit the guard end of the assembly to be tilted up, and locking means on the other side of the bottom face also extending into openings in the bed to prevent said tilting movement.

4. A combination according to claim 3 in which the head carries a block vertically adjustable in said head, and the projecting arm is horizontally slidable in said block.

5. A table saw bed having a plurality of sets of openings therein differently orientated with regard to the saw position, a guard assembly having a head and a flat guard supported from said head; said head having a set of pins adapted to engage any of said sets of openings at will, the pins remote from the saw position being adapted to permit the head to be tilted up about said remote pins, and a pin of said set of pinscloser to the saw position being adapted to hold said head against tilting.

6. A device according to claim 5 in which the guard is provided with a vertically adjustable finger in position to be moved to engage the side face of a work piece.

7. A guard assembly for a rotary table saw having a bed, comprising a head detachably attached to the bed, a block vertically adjustable on said head, a horizontal arm slidable in said block toward and from the saw position including means for locking it in any adjustment, a guard comprising a fiat transparent sheet adapted to be carried by said arm to a position over the saw, said sheet having a vertical end face at right angles to the direction of adjustment of the arm, whereby the sheet may be caused to bear against the side face of a work piece.

References Cited in the file of this patent UNITED STATES PATENTS 394,594 Murray Dec. 18, 1888 596,762 Sevison Jan. 4, 1898 943,129 Vining Dec. 14, 1909 1,090,063 Hook Mar. 10, 1914 1,240,430 Erickson Sept. 18, 1917 1,616,478 Watson Feb. 8, 1927 1,789,357 Ferry Jan. 20, 1931 FOREIGN PATENTS 42,712 Germany Mar. 22, 1888 6,591 Norway Sept. 12, 1898 20,074 Great Britain Nov. 8, 1900 198,130 Great Britain May 31, 1923 

